The present invention relates to an optical sighting device for day or night sighting and more particularly to a reflex sighting device with multiple power sources for illumination of the reticle under different lighting conditions on the object being viewed.
As will be seen, the present invention incorporates some of the concepts in the U.S. Pat. No. 5,653,034 issued Aug. 5, 1997 to Glyn A. J. Bindon for xe2x80x9cReflex Sighting Device For Day And Night Sightingxe2x80x9d and thus the disclosure of that patent should be considered as relevant background for the present invention. As noted in the ""034 Patent, reflex sights are well-known and have taken a variety of forms, such as in gun sights and camera view finders. In substantially all forms, however, some type of reticle pattern is utilized to mark the area or object of interest. Light or the illuminated image from this reticle pattern is reflected from a semi-transparent, semi-reflective mirror or lens surface through which the object or field is viewed. The curvature of the semi-reflecting surface is such as to direct the reflected rays of the reticle image to converge approximately at the same viewing point of the operator as the transmitted rays of the object or field being sighted and thereby to make the reticle pattern appear at infinity and superimposed upon the object or field and at approximately the same distance.
In accordance with the present invention there is provided a reflex sight comprising a reticle and a dichroic beam-splitting mirror for combining rays of light from the reticle with rays of light from an object or field. The dichroic mirror has high reflectance in one part of the visible spectrum and high transmittance in the other parts to provide the dual image to the viewer or operator.
It has been found that in using sighting devices, for example for aiming weapons, cameras and the like, that sighting with both eyes open is advantageous. When sighting with both eyes open, the operator has the benefit of binocular vision which increases the field of view, provides depth perception information, increases contrast sensitivity and assists the sense of balance. The assessment of the speed and direction of moving objects is also more accurate.
As noted, frequently a dichroic mirror is utilized in reflex sights. Such a dichroic mirror reflects nearly all light above one wavelength and transmits nearly all light below that wavelength. If a red or orange dot is used as the aiming mark or reticle, the mirror will reflect red/orange light and transmit yellow, green and blue light from the object being viewed. Thus the dichroic mirror changes the color of a target scene. If the target is viewed with one eye only, the loss of the red color from the target area will be observed. When the other eye is opened, the missing color will be put back into the target scene perceived by the viewer or operator.
Regardless of the type of sighting device, however, it is desirable to provide a limited contrast between the level of brightness of the reticle and that of the target or scene. However, for day and night sighting, the aiming mark contrast can be inconsistent. For example if the aiming mark or reticle is extremely bright it may be most suitable for aiming at brightly lit target scenes but could be too bright for dimly lit target scenes and, of course, the reverse is also true.
Thus aiming at a dark object in heavy shade can be difficult or inaccurate without a suitable means to improve the level of contrast of the aiming mark or reticle. In the past, numerous ways have been devised whereby the aiming mark brightness can be varied to improve contrast with the target scene, i.e. battery powered LEDs (light emitting diodes), etc. which are controlled manually or electronically.
In the present invention a unique construction is utilized to provide selective variation in the reticle brightness in proportion to the target scene brightness in day and night sighting while providing an illumination intensity for day sighting which provides a desired contrast comparable to that of an artificial light source for night sighting.
A fiber optic structure is utilized in which a fiber optic light collector receives ambient light focused transversely or radially inwardly over a selected length of fiber whereby a desired magnitude of light energy can be gathered from ambient light to provide illumination to the reticle. In addition a radio-luminescent source, such as a tritium lamp, is used in combination with the fiber optic collector resulting in a combined illumination whereby a desired level of illumination can be provided to the reticle over the full range of brightness during day and night sighting. At the same time an LED is provided with a variable power source, including a battery, for selectively varying the brightness. In addition a power source, such as a photochemical light source, is provided for selective illumination of the reticle as a back-up for the LED light source in the event of battery failure or other failure of the LED light source.
The LED will not necessarily be continuously energized if the reticle is adequately illuminated by the tritium lamp or by the ambient light being collected. In this regard the present invention utilizes a control system which includes a power controller actuable by the operator for selectively varying the magnitude of voltage and hence power to the LED whereby the intensity of light emitted can be adjusted by the operator. In addition the control system includes a monitor which senses the magnitude of the battery voltage and provides a visual signal to the operator when the voltage falls below a preselected magnitude indicating need to replace it while it is still at an operative level. In addition, however, in the event of loss of sufficient intensity from the tritium lamp source, the LED can be actuated as a back-up to compensate.
The control system also includes a memory structure which will store and remember the magnitude of the battery voltage applied to the LED and resultant level of reticle illumination created before the unit is turned off. Now when the unit is turned on again the magnitude of voltage and hence resultant level of reticle illumination will be at the last level set. Also in the event the system was temporarily disabled by a battery failure or disengagement, upon replacement the magnitude of voltage applied and thus intensity of the illumination to the reticle will be automatically initiated at a level at about the setting for the lowest level of daylight illumination.
In addition, the level of the magnitude of battery voltage applied to the LED will be selectively set by the operator in fixed, stepped increments. Also each activation for a step up or down in voltage magnitude as applied by the operator will be signaled by a short flash or blink of the light of the reticle.
It should also be noted that the magnitude of illumination provided by the tritium lamp can be varied by utilizing a manually variable cover to block more or less intensity of light transmission to the reticle.
Thus it is an object of the present invention to provide a unique reflex sighting device for day and night sighting.
It is another object of the present invention to provide a unique reflex sighting device with improved illumination for the reticle.
It is still another object of the present invention to provide a unique reflex sighting device in which the illumination of the reticle in certain instances is varied naturally in accordance with the illumination of the target or viewing area by an ambient light collector of a unique construction.
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and including multiple power sources for illumination of the reticle.
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and including multiple power sources for illumination of the reticle and with at least one of the power sources being operable by the operator for selectively varying the intensity of the illumination of the reticle.
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and including multiple power sources for illumination of the reticle and with at least one of the power sources being a battery powered LED and including a back-up power source selectively actuable by the operator in the event of failure of the battery;
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and including multiple power sources for illumination of the reticle and with at least one of the power sources being a battery powered LED and including a memory system for automatically placing the LED at a preselected intensity level upon activation of the LED;
It is another object of the present invention to provide a unique reflex sighting device for day and night sighting and including multiple power sources for illumination of the reticle and with at least one of the power sources being a battery powered LED and including a monitor for providing a signal to the operator in the event the voltage drops below a preselected level to provide an advance warning for battery replacement prior to failure;
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. It should also be understood that certain unique features can be considered independently of the numerous combinations noted.